From: Michelle Liu (liujing@u.washington.edu)
Date: Sun Oct 24 2004 - 19:37:29 PDT
Review of "analysis and Simulation of a Fair Queueing Algorithm"
Jing Liu
This paper addresses a fair queueing (FQ) algorithm of gateways and its role in controlling congestion in networks. Compared with first-come-first-serve (FCFS) queueing algorithms, FQ achieves fair allocation of bandwidth, lower delay for sources using less than their full share of bandwidth, and protection from ill-behaved sources.
It's unrealistic to expect a flow control algorithm alone that, when universally implemented throughout a network with FCFS gateways, can provide reasonably fair and efficient congestion control. The FQ algorithm proposed in this paper works well combined with various flow control algorithms. In order to achieve fair bandwidth allocation, a packetized algorithm emulating bit-by-bit round robin scheme is presented. The bandwidth allocation depends on the time of finished service of a packet and the promptness allocation is separated from bandwidth allocation by a nonnegative parameter d, which controls the extent of the additional promptness. Furthermore, ill-behaved sources will be charged for throughput in the FQ algorithm.
One of the weaknesses in this paper is that promptness allocation might require large computational overhead. In addition, the fair allocation is based on conversations or flows or treats each flow 'equally'. However, different flows might have different service requirements. For example, FTP service requires more bandwidth allocation while Telnet service requires low delay. Moreover, priority and preferences could be considered in the allocation of bandwidth, promptness and buffer spaces. Probably a weighted fair queueing scheme could be considered. How to deal with bursty arrivals should also be considered.
This paper does not only provide a scheme to deal with congestion control in networks, but also addresses the issues of QoS and QoS is a necessary research topic in today's networks.
This archive was generated by hypermail 2.1.6 : Sun Oct 24 2004 - 19:37:45 PDT